Stored energy operating mechanism for circuit breaker



Dec. 21, 1965 J, w. MAY ETAL 3,224,280

STORED ENERGY OPERATING MECHANISM FOR CIRCUIT BREAKER Filed April '7, 1964 3 Sheets-Sheet 1 c. 11 A mkoh/a J/L9. '4. 30 5%. WW

geek 9f ie/u zam Dec. 21, 1965 J, w. MAY ETAL STORED ENERGY OPERATING MECHANISM FOR CIRCUIT BREAKER Filed April 7. 1964 3 Sheets-Sheet 2 J. W. MAY ETAL Dec. 21, 1965 STQRED ENERGY OPERATING MECHANISM FOR CIRCUIT BREAKER Filed April '7, 1964 3 Sheets- Sheet 5 United States Patent 3,224,280 STORED ENERGY OPERATING MECHANISM FOR CIRCUIT BREAKER Johp W. May, Walpole, and George K. Benham, Somervllle, Mass., assignors to Allis-Chalmers Manufacturing Company, Milwaukee, Wis.

Filed Apr. 7, 1964, Ser. No. 357,932 9 Claims. (Cl. 74-2) This invention relates to stored energy type of operating mechanisms which may be used with an electric circuit breaker. More particularly, the invention relates to improved means for controlling the operation of such a mechanism.

In the operation of circuit breakers toggles for effecting tripping and closing of the contacts have long been employed in various combinations with different types of latching and tripping arrangements. In some instances it is important to reclose the circuit breaker contacts very shortly after they trip open. This is a complex problem in some trip free operating mechanisms where tripping allows the toggles to collapse thereby rendering the toggles incapable of transmitting closing thrust until reset. Since the resetting operation takes some time, there is a delay in reclosing the breaker after tripping.

Heretofore, some reclosing mechanisms employed hydraulic or pneumatic motors which required the reversal of piston action before the resetting operation could be completed and this also restricted the reclosing time of the breaker. Solenoid operating mechanisms have been used in place of hydraulic or pneumatic motors and, although the force output characteristics of a solenoid is ideal, the solenoid is useless if its source of electrical energy is temporarily lost. Furthermore, a solenoid increases in both cost and sluggishness with increase in size.

Stored energy closing devices have been provided which closely duplicate the increasing force characteristics of a solenoid closing mechanism. This type of device not only overcomes the problem of cost and time delay aforesaid but also is ready for use if electrical power to the closing motor is temporarily lost. In one type of stored energy operating mechanism for circuit breakers employs a relatively movable contact structure. A tripping means is arranged for controlling the contact structure and comprises a first collapsible toggle having one link thereof connected to the contact structure. Spring means are provided for causing collapse of the first toggle and actuation of the contact structure in a given direction. Means including a latch are provided for preventing collapse of the first toggle. A further means associated with the latch is utilized for releasing the latch at a particular time. Actuating means comprising a second overcenter toggle are provided for driving the first toggle to its overcenter position to actuate the contact structure in a second direction and to charge the spring means. The second toggle engages the knee of the first toggle during movement of the second toggle to its overc-enter position and actuates the first toggle to its overcenter position. In this type of operating mechanism the decaying force characteristics of force transmitting springs are matched to the increasing force characteristics of a toggle operating means. Thus, the force necessary at the end of the closing stroke of the circuit breaker contacts can readily overcome the high magnetic forces encountered when closing in against a short circuit current without producing damaging contact velocities when closing in against a no load condition.

In one version of this type of operating mechanism the closing springs are charged by pivoting a walking beam by means of a spiral cam. As the cam rotates, the walking beam drops oil the high point of the cam and 3,224,280 Patented Dec. 21, 1965 moves into position on a prop latch. Since the closing springs are held in charged condition through a system of at least three links and one toggle, close tolerances of parts has to be maintained. Furthermore, since the tripfree latch does not reengage until the closing springs are being recharged, the closing toggle of the four bar linkage is able to collapse. 7

In accordance with the present invention, a new and improved operating mechanism is provided in which the closing springs are charged by a rotating gear to drive a free swinging crank to force a two-link toggle overcenter. This permits a prop to bear gradually the increased force of the closing spring as it is charged from no load to full load without shock or impact and also eliminates the need for extremely close tolerances. In addition, the trip-free latch resets instantaneously after opening of the circuit breaker, regardless of the position of the charging springs because the spring charging toggle links collapse immediately after closing and do not interfere with the four bar linkage in any position.

It is, therefore, one object of this invention to provide a new and improved actuating means.

Another object of this invention is to provide a new and improved stored energy type of operating mechanism employing a new arrangement for controlling the operation of this mechanism and for charging the closing springs.

A further object of this invention is to provide a new and improved stored energy type of operating mechanism which is relatively simple nad inexpensive to manufac ture and operates to prevent circuit breaker pumping in the event the breaker is closed on a fault.

A still further object of this invention is to provide a new and improved stored energy type of operating mechanism which can be successfully operated by a small electric motor of minimum size and force output.

A still further object of this invention is to efiect high speed resetting of the circuit breaker mechanism which does not interfere with the opening of the breaker but is capable of providing resetting forces which are maintained at a high level from the instant of tripping until resetting is completed.

Objects and advantages other than those set forth will be apparent from the following description when read in connection with the accompanying drawings, in which:

FIG. 1 is a view in vertical cross section of a magnetic blowout type of circuit breaker employing the present invention;

FIG. 2 illustrates schematically the condition of the; circuit breaker operating mechanismwherein the contacts 1 are open, the closing spring is discharged, the opening spring is discharged, prop latch closed, and trip latch closed;

FIG. 3 illustrates schematically the condition of the circuit breaker operating mechanism wherein the contacts are open, the closing spring is charged, the opening spring is discharged, prop latch closed, and trip latch closed;

FIG. 4 illustrates schematically the condition of the circuit breaker operating mechanism wherein the contacts are closed, the closing spring is discharged, the opening spring is charged, prop latch open, and trip latch closed;

FIG. 5 illustrates schematically the condition of the circuit breaker operating mechanism wherein the contacts are open, the closing spring is discharged, the opening spring is discharged, prop latch closed, and trip latch open; and

FIG. 6 illustrates schematically the condition of the circuit breaker operating mechanism wherei the contacts are open, the closing spring is charged, the opening spring is discharged, prop latch closed, and trip latch open.

Referring more particularly to the drawings by characters of reference, FIG. 1 illustrates a magnetic blowout type of circuit breaker employing a arc chute into which the arc is forced by the magnetic blowout field and extinguished. The power circuit to be interrupted includes relatively movable contacts between which the arc is formed when the contacts separate at the entrance to the arc chute. Specifically, the contacts comprise a fixed contact structure 11 and a coacting movable contact structure 12. The fixed contact structure is electrically connected to a lead in conductor stud 13 defining one terminal of the breaker, and the movable contact structure 12 comprising a pivoted switch arm having an arcing contact mounted at one end thereof is electrically connected to a conductor stud 15 defining the other breaker terminal. The pivoted contact structure 12 is suitably operated between open and closed circuit positions by an operating rod 16 that is connected through a crank 17 to a motor drive actuating means 18.

FIG. 1 illustrates the movable contact structure 12 in contact open position, the coacting main and arcing contacts 20 and 22, respectively, of the movable contact structure 12 being spaced apart from corresponding main and arcing contacts 23 and 25, respectively, of the fixed c011- tact structure 11. A pair of lugs 21 (one of which is shown in FIG. 1) is integrated with arcing contact 22 and extends from opposite sides of a web portion of arcing contact 22. Lugs 21 together with the web portion of the arcing contact 22 form an engaging surface which coacts with that of a block of insulating material 24 on the stationary contact structure 11 to limit overtravel of the movable contact structure 12 in the closing direction. In breaker closed position the stationary arcing contact 25 is shunted by stationary main contact 23. Opening of the breaker by the clockwise rotation of the breaker movable contact structure 12 causes, in the sequence named, separation of the main current carrying contacts 20, 23 and the arcing contacts 22, 25. The power are is formed at the entrance of an arc chute 26.

Are chute 26 is illustrated as being provided with magnetic blowout means comprising blowout coils 28 and 29 arranged so as to cause the arc formed between the contacts 22 and 25 to be blown by the magnetic field into arc chute 26. Blowout coil 28 is connected at one end thereof to a conductive arc runner 30 and at the other end thereof immediately adjacent main contact 23. Blowout coil 29 is connected at one end thereof to a conductive arc runner 31 and at the other end thereof to a lower terminal extension 32 through a conductive bar 27.

Upon separation of the arcing contacts 22 and 25 in a circuit interrupting action the arc terminal is transferred from stationary arcing contact 25 to are runner 30, thereby inserting blowout coil 28 in the arcing circuit traced from the point of connection of blowout coil 28 on the upper terminal block immediately adjacent main contact 23 through blowout coil 28 to arc runner 30, through the arc to movable arcing contact 22. As the are, now established between arc runner 30 and the movable arcing contact 22, is attenuated by the clockwise rotation of contact structure 12, the arc envelops the lowermost portion of arc runner 31 thereby transferring the arc terminal from arcing contact 22 to arc runner 31 and inserting blowout coil 29 in the arcing circuit. The arcing circuit is now completed through the bar 27 which connects the blowout coil 29 with the lower terminal extension 32.

The arcing contact structure and the arc chute of the circuit breaker structure are mounted on a supporting structure comprising a fabricated vehicular base structure 35. Mounted on base structure 35 is the circuit breaker operator 18 which may be a motor driven circuit breaker movable contact actuating means. A pair of dual purpose substantially vertical or diagonal tubular members 36 (one of which is shown in FIG. 1) are provided on base structure 35. Members 36 are connected to a horizontally arranged manifold 39 which supports a pair of horizontal cross bracing means 37 (only one of which is show in FIG. 1). The circuit breaker elements comprising the movable contact mechanism of the circuit breaker and the arc chute are mounted on the horizontal cross bracing means 37 and the manifold 39. Members 36 in addition to supporting the circuit breaker, further collect and distribute to a zone of arc initiation fluid under pressure from a source of fluid under pressure such as a suitable pneumatic means 38 used for aiding in cooling and extinguishing an are drawn by the circuit breaker elements between the arcing contacts.

This pneumatic means may be an air pump comprising, a cylinder 40 mounted on base structure 35 and a piston, 41 movable in cylinder 40. Piston 41 is biased in contact opening direction by an operating spring 42 which is one means for opening the circuit breaker. The motor operat ing means 18 through crank 17 returns piston 41 to itsupper position simultaneously with a circuit breaker closing operation, thereby placing spring 42 under tension so it is capable of again opening the circuit breaker contacts. Any suitable means such as pipe connections 45 may be used for connecting the substantially vertically arranged tubular members 36 to the source of fluid under pressure, namely cylinders 40. For the purpose of aiding in the interrupting of the arc the switch arm or movable contact structure 12 is connected to piston 41 through operating rod 16 and crank 17. Upon the movement of contact structure 12 from closed to open circuit position under the action of springs 42, piston 41 is actuated and moved from the top of cylinder 40 to the bottom of cylinder 40. This movement of piston 41 causes air in cylinder 40 under piston 41 to flow through pipe connections 45, tubular member 36, manifold 39, tubular member 46, bearing 43, tubular member 47 and nozzle 44 to the zone of arc initiation.

Arc chute 26 is provided with a group of slotted, spaced insulating plates 48 arranged to extend longitudinally of the axis of the chute and transversely to the arc at the arc receiving end thereof and a pair of chimney vents 49 and 50 arranged longitudinally of the axis of the chute one adjacent each of the arc runners 30 and 31. The insulating barrier plates 48 may be arranged in a combination having a plurality of types of barrier plates having different geometrical configurations. Slots 51 of barrier plates 48 are aligned at their upstream ends adjacent the zone of arc initiation to form an arc passage. As well. known in the art, the slots may be arranged in staggered relationship at their downstream ends. This out of regis try or staggered relationship of the slots causes the formation of a zigzag shaped arc path.

The operating mechanism 18 comprises a driving shaft 50 having fixedly mounted thereon a pinion 50a. Shaft 50 is understood to be rotated by means of a motor 50b through a suitable gear train 500 or by means of a manually rotatable crank or handle 52b. Pinion 50a engages and drives a spur gear 51 which is rotatable about a shaft 51a. A free swinging driving crank or cam 52 is rotatable about shaft 51a and is adapted to be driven in a counterclockwise direction by a pin 53 mounted on the face of spur gear 51. Upon counterclockwise rotation of spur gear 51, pin 53 thereon engages driving crank 52 and causes it to rotate. Driving crank 52 engages a roller 54 which is mounted on a toggle link 63 of an overcenter toggle 62. Toggle link 63 is pivotally connected at one end to a toggle plate 55 which has a slot 55a for accom-- modating a pin 56a on a bar or member 56. Toggle plate 55 is provide to connect toggle 62 to bar 56 in such a manner as to allow for some play in the connection and to aid in force transmission as hereinafter described. Plate 55 is pivotally mounted to the supporting frame as shown in FIG. 2 and is understood to lie in a different plane than bar 56 so that bar 56 can move therepast to various operating positions. Bar 56 is pivotally supported at one end on the supporting frame and is connected at its other end to a load spring means or closing spring 57. En-

gagement of crank 52 with roller 54 as gear 51 rotates causes toggle 62 to move from its fully collapsed position, shown in FIG. 2, to its extended position, shown in FIG. 3. As FIG. 3 shows, link 63 of toggle 62 is provided with an abutment or projection 63a which engages an end portion 61a of link 61 to prevent downward collapse of toggle 62 as the latter is moved to extended position. As FIG. 4 shows, link 63 of toggle 62 is provided with a member 63a, which is in the form of an adjustable screw, which is adapted to be struck by bar 56 near the end of the discharge stroke in order to force toggle 62 upward.

The motion of bar 56 to the left extends or charges load spring means (stored energy device) 57 which is attached at one end to the frame and at its other end to the bar. A latch roll 59 is rotatably attached to the end of a link 61 of toggle 62. As spring means 57 is being charged by the movement of bar 56 to the position shown in FIG. 3, latch roll 59 of toggle 62 engages a prop latch 65 which holds the fully charged spring latched and ready to be discharged to perform a useful function, for example, closing of the movable cooperating contact structures 11 and 12 of the circuit breaker. Prop latch 65 comes into engagement with latch roll 59 due to the action of a tension spring 65a which moves link 62 from the position shown in FIG. 4 to the position shown in FIG. 5. The prop latch 65 may be released or tripped by a solenoid mechanism (not shown) upon movement of its armature 65'. The release of prop latch 65 from its position shown in FIG. 3 permits bar 56 to move to the right as shown in the drawings under the force of spring means 57. As FIG. 6 shows, after gear 51 has stopped rotating, crank 52 must be moved to a position where it is in readiness for the next cycle of operation. As FIG. 4 shows, this comes about when toggle 62 collapses and in doing so strikes the free swinging crank 52 and swings it counterclockwise so that it comes to rest against pin 53. Once the stored energy of load spring means 57 has been released the spring means can again be recharged automatically by motor 50b or manually by the handle 52b as explained above.

After the crank 52 has rotated past roller 54 and spring means 57 has been fully charged and the prop latch 65 has held it in position, motor 50b is deenergized by a suitable switch (not shown) mechanically associated with and responsive to the position of toggle 62. It is to be understood that in practice operating mechanism 18 is provided with a suitable supporting frame and that the frame and mechanism are attachable and removable as a unit from circuit breaker housing 58.

As shown in FIGS. 3 and 6 contact structures 11 and 12 are in their contact open position when the stored energy spring means 57 is charged. spring means 57 is connected to the contact structures 11 and 12 by means of an overcenter toggle 70. One link 71 of toggle 70 is connected to crank 17 which is pivotally mounted at 72 to the frame of the circuit breaker operating mech anism which is attached to the housing 58 of the circuit breaker structure. The other link 73 of toggle 70 is pivotally mounted on one end of crank 74 which in turn is pivotally mounted at point 75 to the housing of the circuit breaker structure. An arm 76 is pivotally mounted at one end to the frame of the circuit breaker structure at point 75 and is pivotally connected at its other end to the roller end of overcenter toggle 62.

When prop latch 65 is released by the solenoid mechanism (not shown) and rotates clockwise it releases latch roller 59. Roller 59 and link 61 of overcenter toggle 62 rotate clockwise coming in contact with a roller 77 which interconnects links 71 and 73 and forms the knee of overcenter toggle 70. Latch roller 59 drives roller 77 and overcenter toggle 70 past its overcenter position until roller 77 reaches arcuate stop 78 as shown in FIG. 4. The movement of toggle 70 to its overcenter position causes crank 17 to rotate counterclockwise to cause engagement of the contact structures 11 and 12.

At the instant that overcenter toggle 70 is moved to its overcenter position against stop 78, latch roll 79 mounted on pin 80 interconnecting link 73 of toggle 70 and crank 74 engages a prop latch 81 affixed to the housing of the circuit breaker, thus holding the contact structures 11 and 12 closed against the force of their contact opening spring 42. Spring 42 which is diagrammatically illustrated as being connected between crank 17 and the housing of the circuit breaker structure is charged by the contact closing mechanism described. Upon release of toggle 70 from its overcenter position by prop latch 81 spring 42 opens the contact structure. The prop latch 81 may be released or tripped by a solenoid mechanism 82 which upon movement of its armature 83 downward as shown in FIGS. 5 and 6 actuates the prop latch 81 to rotate it clockwise releasing latch roll 79, thereby permitting the overcenter toggle 70 to collapse to the position shown in FIGS. 5 and 6.

Upon deenergization of solenoid mechanism 82, armature 83 assumes its normal position shown in FIG. 1 and spring 84 on latch prop 81 biases it back to its latch engaging position shown. Before spring 84 can return latch 81 to its normal position, a spring 74a connected to one end of crank 74 rotates crank 74 counterclockwise to effect collapse of toggle 70 to the position shown in FIG. 2. As previously stated, before toggle 70 can collapse, toggle 62 must be in collapsed condition.

In accordance with the invention claimed motor 59b is energized whenever the spring means 57 is discharged. This occurs by the use of an electrical switch 56c shown in FIGS. 2, 3 and 4, associated with the position of toggle 62. More specifically, bar 56 which is movable by toggle 62 comprises a portion 56b which is adapted to move into and out of engagement with switch 560 to operate it. When'switch 56c and portion 56b are disengaged, motor 50b is energized. When switch 560 and portion 56b are engaged, motor 50b is deenergized. Thus, motor 50b through its associated gearing 50c rotates gear 51 counterclockwise to drive crank 52 against latch roller 54. This action first causes upward movement of toggle 62, but as the clockwise rotation of bar 56 continues, toggle 62 is moved downwardly thereby charging spring means 57. During the spring charging operation prop latch 65 holds latch roller 59 and toggle 62 in a given position and motor 50b drives gear 51 counterclockwise until it reaches the position shown in FIG. 3 whereupon motor 50b is deenergized. Upon release of latch prop 65 by a solenoid mechanism similar to mechanism 82, toggle 62 moves from the overcenter toggle position shown in FIG. 3 thereby driving by means of latch roll 59 on toggle 62, latch roller 77 and toggle 70 to their overcenter position against stop 78. The movement of toggle 70 to its overcenter position causes the closing of the contact structures 11 and 12.

As soon as the contact structures 11 and 12 have been closed and their opening spring 42 charged upon movement of toggle 62 from its overcenter position, motor 501) is energized and spring means 57 recharged. However, during the instant that toggle 62 remains in its discharged position as shown in FIG. 4, the contact structures 11 and 12 may be tripped open to the position shown in FIGS. 5 and 6 by energizing solenoid mechanism 82 resulting in clockwise rotation of prop latch 81. Release of crank 74 causes clockwise rotation thereof under the force of spring 42 resulting in opening of contact mechanism 11 and 12 without interference with toggle 62. The resulting trip free movement of contact mechanisms 11 and 12 is shown in FIG. 6.

As noted from the drawing, approximately one revolution of gear 51 charges spring means 57. The gear 51 is so provided that an equal torque is imposed on motor 50b for the whole of the revolutions in question. Energy is impressed on the spring at an equal rate throughout the charge revolution of motor 50b. Further by the use of a double toggle mechanism in combination with spring stored energy devices the contact closing operation is accomplished by the release of energy from spring means 57. This occurs as toggle 70 is moved to its extended and overcenter position by toggle 62 as the latter is moved from its extended position by spring 57. Thus, as spring means 57 reaches its most weakened condition (its energy almost completely spent) the toggle mechanisms reach their highest mechanical advantage. A large contact closing force is available near contact closed position on springs which have given up most of their energy. It is to be noted that at the start of the discharge of spring 57, plate 55 is initially in the position with respect to toggle 62 as shown in FIG. 3. During discharge of spring 57, toggle 62 acts as a single member in transmitting force and plate 55 cooperates therewith in its toggle action. During discharge of spring 57, plate 55 pivots in a counterclockwise direction to afford an increasing mechanical advantage whereby the force on toggle 70 remains constant even though the force exerted by spring 57 is diminishing.

Although but one embodiment of the present invention has been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In an operating mechanism having a first toggle movable from a collapsed position to an overcenter position, actuating means for moving said first toggle to said overcenter position, said actuating means comprising, in combination, a second toggle movable from a collapsed position to an extended position, a spring operatively connected to said toggle and movable from discharged to charged condition by said second toggle as the latter moves to its extended position, releasable latching means for maintaining said second toggle in extended position and said spring in charged condition, and means for moving said second toggle from collapsed position to its extended position, said means comprising a gear rotatable about an axis and having a projection thereon, and a crank rotatable with respect to said gear about said axis and adapted to be engaged by and rotated by said projection on said gear, said crank being adapted to engage said second toggle to move said toggle to extended position.

2. In an operating mechanism having a first toggle movable from a collapsed position to an overcenter position, actuating means for moving said first toggle to said overcenter position, said actuating means comprising, in combination, a second toggle comprising two links and movable from a collapsed position to an extended position, a spring operatively connected to said second toggle and movable from discharged to charged condition by said second toggle as the latter moves to its extended position, releasable latching means for maintaining said second toggle in extended position and said spring in charged condition, a gear rotatable about an axis and having a projection thereon, a crank rotatable with respect to said gear about said axis and adapted to be engaged by and rotated by said projection on said gear, and crank engaging means on one link of said second toggle adapted to be engaged by said crank as the latter rotates to cause movement of said second toggle to its extended position.

3. The combination according to claim 2 wherein, upon release of said latching means, movement of said spring to discharged condition effects collapse of said second toggle and said crank engaging means comprises a portion which strikes said crank to move said crank into position for its next cycle of operation.

4. In an operating mechanism mounted on a support having a first toggle movable from a collapsed position to an overcenter position, actuating means for moving said first toggle to said overcenter position, said actuating means comprising, in combination, a second toggle comprising two links and movable from a collapsed position to an extended position, a member movable from one position to another, said member being operatively connected to one end of said second toggle, a spring connected at one end to said member and at its other end to said support and movable from discharged to charged condition by movement of said member from its one position to its other position, a gear rotatable about an axis and having a projection thereon, a crank freely rotatable with respect to said gear about said axis and adapted to be engaged by and rotated by said projection on said gear, means effecting rotation of said gear when said member moves to its said one position and for stopping rotation of said gear when said member moves to its said other position, crank engaging means on one link of said second toggle adapted to be engaged by said crank as the latter is rotated by said projection on said gear to cause movement of said second toggle to its extended position, and releasable latching means for maintaining said second toggle in its extended position and thereby maintaining said member in its said another position and said spring in charged condition.

5. The combination according to claim 4 wherein said crank and said crank engaging means comprise cooperating portions whereby upon movement of said second toggle from its extended position to its collapsed position, said cooperating portion on said crank engaging means strikes said cooperating portion on said crank to eltect rotation of said crank to a position placing it in readiness for its next cycle of operation.

6. The combination according to claim 5 including means connected between said member and said second toggle for cooperating with the latter in moving said first toggle so that the force transmitted to said first toggle remains constant even as the energy of said closing spring diminishes.

7. The combination according to claim 1 including a member movable from one position to another and operatively connected to said second toggle and to said spring, said member being in said another position when said second toggle is extended and said spring is charged.

8. The combination according to claim 7 including means connected between said member and said second toggle for cooperating with the latter in moving said first toggle so that the force transmitted to said first toggle remains constant even as the energy of said closing spring diminishes.

9. The combination according to claim 8 wherein said means comprises a plate pivotable about a point, pivotably connected to said second toggle, and slidably connected to said member, said plate being adapted to transmit force from said member to said second toggle as said member moves from said other position to its said one position.

References Cited by the Examiner UNITED STATES PATENTS MILTON KAUFMAN, Primary Examiner. 

1. IN AN OPERATING MECHANISM HAVING A FIRST TOGGLE MOVABLE FROM A COLLAPSED POSITION TO AN OVERCENTER POSITION, ACTUATING MEANS FOR MOVING SAID FIRST TOGGLE TO SAID OVERCENTER POSITION, SAID ACTUATING MEANS COMPRISING, IN COMBINATION, A SECOND TOGGLE MOVABLE FROM A COLLAPSED POSITION TO AN EXTENDED POSITION, A SPRING OPERATIVELY CONNECTED TO SAID TOGGLE AND MOVABLE FROM DISCHARGED TO CHARGED CONDITION BY SAID SECOND TOGGLE AS THE LATTER MOVES TO ITS EXTENDED POSITION, RELEASABLE LATCHING MEANS FOR MAINTAINING SAID SECOND TOGGLE IN EXTENDED POSITION AND SAID SPRING IN CHARGED CONDITION, AND MEANS FOR MOVING SAID SECOPND TOGGLE FROM COLLAPSED POSITION TO ITS EXTENDED POSITION, SAID MEANS COMPRISING A GEAR ROTATABLE ABOUT AN AXIS AND HAVING A PROJECTION THEREON, AND A CRANK ROTATABLE WITH RESPECT TO SAID GEAR ABOUT SAID AXIS AND ADAPTED TO BE ENGAGED BY AND ROTATED BY SAID PROJECTION ON SAID GEAR, SAID CRANK BEING ADAPTED TO ENGAGE SAID SECOND TOGGLE TO MOVE SAID TOGGLE TO EXTENDED POSITION. 